Baffle wall for drainage ditches



'Dec. 31), 1924,. L52LU E. BERN BAFFLE WALL FOR DRAINAGE DITGHES FiledNov. 2, 1923 2 Sheets-Sheei 1 E. BERN BAFFLE WALL FOR DRAINAGE DITCHESDeg 30, 1924.

' 2 Sheets-Sheet 2 Filed Nov. 2, 1925 HTED STATES Para raise.

EMIL BERN, or DES Monies, IOWA.

BAFIELE WALL FOR DRAINAGE DITCHES.

Application filed November 2, 1923. Serial No. 672,317.

To all whom it may concern:

Be'it known that I,'EMIL BERN, a citizen of the United States, and aresident of Des Moines, in the county of Polk and State of Iowa, haveinvented a certain new and useful Baffle Wall for Drainage Ditches, ofwhich the following is a specification.

The purpose of my invention is to provide a baflle wall of simple,durable and inexpensive construction for drainage ditches and the like.

Generally speaking, it is my object to provide a baffle wall of novelconstruction having a number of advantages hereinafter 'more fullyreferred to.

More particularly, it is my object to prow vide a baffle wall adapted tobe placed in a drainage ditch or the like, comprising a central portion,which in the preferred form of my invention, has substantially the formof a half circle opening downwardly with relation to the flow of waterin the ditch and having end portions which in the preferred form areconnected with the central portion and open upwardly with relation tothe flow of water in the ditch.

A further purpose is to provide in such a baffle wall horizontalcorrugations or their equivalents for accomplishing a variety ofpurposes hereafter explained.

Another object is to provide in such a baflie wall a transverse bracefor the upper ends of the end portions.

With these and other objects in View, my invention consists in theconstruction, arrangement and combination of the various parts of mydevice, whereby the objects c ontemplated are attained, as hereinaftermore fully set forth, pointed out in my claims, and illustrated in theaccompanying drawings, in which:

Figure 1 shows an elevation of my baflle wall viewed from the upper partof the ditch. a

Figure 2 shows a top or plan view of the same. I

Figure 3 shows a longitudinal, vertical, sectional View of the ditch,showing two of the spaced walls in section.

Figure 4 shows a vertical, sectional view taken on the line H of Figure1.

Figure 5 shows an enlarged,'vertical, sectional view taken on the line55 of Figure 1, looking in the direction indicated by the arrows,

Figure 6 shows a plan view of a portion of one end of the baflle walland the ditch illustrating somewhat in diagram one of the functions ofthe end member.

Figure 7 is a diagrammatic view illustrating the flow of water over thecentral portion of the baflie wall, as viewed from above.

Figure 8 shows an elevation similar to the view shown in Figure 1 of anend of the baffle wall of a slightly modified form; and

Figure 9 shows atop view of another modification ofmy invention.

I will first describe the structure of my baflle wall in a preferredform in which it may be embodied and will then explain the purposes andfunctions of the wall and some of the advantages resulting from itsstructure for accomplishing these purposes and functions.

In modern road building, it is the custom to provide drainage ditches atthe sides of the highway. Where the road is not level,

but is located on a hillside of greater or less inclination, thebuilding of these ditches becomes amatter of great importance for thereason that in times of heavy rains and when the flow of water isconsiderable, the

ditcjllies wash out and sometimes destroy the roa .It is a matter ofprime necessity that the ditches be so constructed and that such meansbe provided as to provide for the carrying off of water by the ditcheswith a minimum washing of the ditches and minimum injury to the highway.

In general practice, where t e road is, inclined from the level, it ishe custom to provide at the side of the road, ditches which usually areabout eighteen inches wide at the bottom.

Heretofore, it has been found that in order to reduce the washing to aminimum, it is desirable at certain intervals depending upon the fall ofthe ditch and upon the condition of the soil, the size of the ditch andso forth to provide in the ditch bafile walls.

The common practice has been to place a straight, transverse wooden wallin theditch. These wooden walls have been subject to many disadvantageswhich will be again referred to in connection with the explanation ofthe functions, purposes and advantages of my baflie wall. Suflice it tosay for the present, that the wooden baflie walls are not satisfactoryand have simply been used for lack of something better.

Referring now to the preferred form of my bafiie wall, as shown in thedrawings, I have used the reference numeral 10 to indicate generally thecentral member of my bafile wall, which consists of a vertical,semicylindrical element. This element I preferably make of galvanizediron, but it will, i

of course, be understood that it can be made of a variety of materialsand that any material suitable for the purpose can be used.

' Connected with each side edge of the central, member 10'is an endmember 11. The members 11 are preferably substantially semi-cylindricalas shown for instance in Figure 2, opening in theopposite'direction fromthe opening of the member 10.

When the bafiie wall is installed in the ditch, the central member opensdownwardly with relation to the water flow and the members 11 openupwardly, as illustrated.

It may, of course, be mentioned that the degreeof curvature of themembers 10 and 11 may be'varied, and it would be possible to use othershapesto accomplish generally my purpose. a

The members 10 and 11 are preferably provided with horizontalcorrugations 12, which might have the form of ribs, shoulders orotherwise to accomplish the functions of such corrugations hereinaftermore fully explained.

The baffle Walls herein described are set in the ditch with the member10 at the center of the ditch at thebottom thereof and the members 11embedded in the side Walls. The height and width of the members 10 and11.will, of course, vary according to the service to be required of thebaffle walla For purposes of illustration, I might say that in anordinary ditch eighteen inches wide at the bottom, I make the member-10approximately four 'feet in height and vary its shape from a half circlein horizontal section, so thatthe distance from side edge to side edgeis substantially two feet, and in the particular size of battle wall nowbeing used for illust'ration, the height of the central member from topto bottom is four feet. I

In the particular wall now under consideration, the members 11 are alsotwo feet on a straight line from side edge to, side edge and four feetaround the curve of the member from side edge to side edge.

In Figure 1, Ihave shown. the members 11 projecting above the member 10at their edges adjacent thereto approximately four inches and have shownthe upper edges of the members 11 inclined upwardly from their inneredges to their outer edges, so that the outer edge of the end member 11stands about twelve inches above the member 10 and this angle ofinclination may be varied as necessary for the particular job.

In the actual process of manufacture, where the device is made ofgalvanized sheet metal, I use sections so that each'member 10 is madeof, two sections as illustrated in Figure 1, and each member 11 ismadeof two sections and-a portion of the third section. c

If a comparatively low bafile wall is necessarythen only one section inheight is required.

In Figure 8, I have shown a slightly modified form of the end membersindicated by the number 11 in which a portion indicated atA is cut offthe bottom of the end member and is secured to the upper section of theend member to form that portion of the end member which' projects abovethe level of the central member. tions will permit this structure, iteffects a substantial saving of material.

It will be understood that the height of the end members above thecentral member will vary according to the service required of the battlewall.

In Figure 3, I have shown a section of a Where condi ditch in order toillustrate the arrangement of two of the bafflewallswith relation toeach other. In actual practice, I preferto install bafile walls in theditch with the upper edge of the member 10 substantially The sidemembers 11 are practically entirely banked and covered with dirt on theup-sideportion of the ditch, the outline of the ditch being indicated bythe dotted line 13 in Figure 1. The outline of the ditch on the downsideof the batiie wall is indicated gen-' erally by the dotted line 14 inFigure 1.

In the bottom of the ditch where the water falls over the member 10something better than a dirt bottom may beprovided. In Figure 3, I haveshown a pile of stones 15. Any bottom, which will reduce washing to aminimum may be employed. The bottom of the ditch from baflie wall tobathe wall may be inclined or sloped slightlyas shown in Figure 3depending on soil conditions. In Figure 9, I have shown another slightlymodified formof my invention, which might be desirable to be employedunder special circumstances, as for instance where the walls might beinstalled in a ditch that had washed badly. j In the formshown in Figure9, I have shown connected with the outer portions ofthe members 11curved wings 16. which may be made of a portion of material similar tothe members 11, but are preferably lighter.

I will now explain some of the uses and advantages-of my improved bafliewall.

It will be understood that the general purpose of a bafile wall anddrainage ditch is to control the flow of water and reduce washing of theditch. This is accomplished by bafile walls by virtue of reducing thevelocity and momentum of the flow of water. This reduction isaccomplished by causing the water to flow over the baflie walls with adrop and then to flow from one baflie wall to another in a ditch havinga comparatively slight slope lnstead of permitting the water to flowdown in a long ditch having a greater slope.

There is then involved the problem of providing the most eflicient bafiewall for accomplishingthe purpose of-reducing the velocity and momentumof the water with a minimum washing of the ditch at the point where thebafiie wall is installed.

These general purposes I have provided for in the structure, arrangementand installation of my bafl'le wall. 4

Referring now to the straight walls here-. tofore used, it may bementioned, that when such walls are employed, the water flows from theup-side of the wall into the portion of the ditch on the down-side ofthe wall with a substantial fall of for instance two feet. The fallingwater washes a hole below the wall and the water usually forms an islanda little farther down the ditch. Even after the high water goes down andthe flow of the water is substantially reduced, the island will tend todivert the flow of water in the ditch and will cause the Water to eatinto the sides of the ditch which is an undesirable result. The islanddirects the water below the balle wall outwardly against the side wallsof the ditch frequently causing a bad washmg of the ditch wall, at thatpoint. This undesirable result 1s prevented where my wall is employed byreason of the fact that the water instead of flowing over aneighteen-inch or even a twenty-four inch straight Wall, as in the casewhere a straight wall is employed, flows over acurved wall four'feet inlength and the water does notfall over a straightwall and then downbutover a curved wall, so that the water flowing in.from the side mingleswith the water flowing over the central portion of the central member 10with the result that in actual practice, the force of the water is socontrolled that the island-mentioned does not form to anywhere nearlythe sameve'xtent as where a straight wall is used. It maybe mentionedthat where rock or other solid bottom is placed in the member that noisland willbe formed,

I dirt.

the solid bottom preventing the water from gouging out between the wallsof the members 10 and 11.

.Where astraight wall is employed, the churning of the water on thedown-side of the wall washes out the side walls of the ditch along thelower face of the baflie Wall and washes the dirt away from the bafflewall.

Where my Structure is employed, the churning effect of the water inwashing away the dirt of the ditch at the side of the ditch is preventedby the fact that the water falls into a channel protected at its sidesby the curved wall of the member 10 and by the curved walls of themembers 11.

I therefore practically doaway with the washing of the side walls of theditch immediately adjacent to the baffle wall on the down-side of thebattle Wall.

Thus the ditch does not wash out close to the Wall on the down side ofthe Wall where my device is used to anywhere nearly so great a degree aswhere a straight wall is employed.

Furthermore, where a straight wall is employed, it will be rememberedthat during a rain, water travels down the sides of the ditch to thebottom of the ditch in little streams and rivulets. These little streamsand rivulets come down to the straight wall and find there, forinstance, the edge of a two inch plank surrounded by soft refill Theybegin to wash out the dirt to provide a path not only for the streamletsflowing down the side wall of the ditch but also for the main stream ofwater flowing down the ditch. When this occurs, the dirt at the end ofthe straight baffle wall is washed away very rapidly leaving the ends ofthe baffle wall exposed. Dirt is then washed away from the up-side ofthe battle wall near the end, and oftentimes out deep enough to permitthe main channel of the stream to pass around the edge of the wall.

It thus frequently occurs in actual use of the straight walls thatenough dirt is washed away from the down-side of the baffle wall so thatthe battle wall begins to tilt forwardly from its upper position and ina very short time is washed entirely out.

I have already expained why the dirt will not wash away fromthe.down'-side of the central portion 10. f

I will now explain why the dirt will not wash away .from the outer edgesof the members 11. It will be noted that if the distance from the pointindicated by the arrow 17 in Figure Qto the point indicated by thearrow'at 18 in Figure 2, being substantially the radius of the circle onwhich the member 11 is formed, is approximately one foot, there is awallof dirt a foot in length against the outer portion of the member 11,which must be washed away and moved downstream before water can begin toflow around the outer edge of the member 11. I

In actual practice, I find that the little rivulets flowing down theside wall of the ditch toward the member 11 do not move this foot ofsoil, because of its weight and inertia, but these little rivulets tendto flow up-stream' from the member 11 or downstream from the member 11,thus forming a ridge up the side wall of the ditch from the outerportion of the member 11.

It follows, of course, that the little rivulets avoid this ridge andflow down at the sides thereof, so that the ridge rem-aips to protectthe outer edge of the member 11 and the dirt at the outer edge of themember 11 does not wash out.

It has already been noted that owing to the fact that the water flowingover the member 10 flows not only in a direction down stream, but alsotowards the center of the stream on account ofthe curvature of themember 11, the earth on the downside of the member 11 is not washed awayon the down-side of the member 11 as in the case of a straight wall.

This fact combined with the facts already mentioned that the earth doesnot Wash away at the outer edges of the members 11 on account of thepeculiar structure of my wall permits my wall 'to remain firmly andrigidly installed in position where a straight wall would have washedout.

In this connection, it will be noted that in' bad places, the wing 16,such as is shown in Figure 9, increases the functional operation of theouter portions of the members 11 in preventing the washing away of dirtaround the ends of the baffle wall.

It will be noted also with the curved form of wall herein shown, itwould be necessary in order to wash out enough dirt to permit the wallto tilt forwardly at its upper portion and then wash out to move a greatdeal more dirt than would have to be moved to permit a straight wall totilt down-stream.

It will, therefore, be noted that my bafiie wall as herein shown drawsthe water away from the bank side walls at the point where the maximumflow occurs over the member 10, thus reducing the wash on the side wallsof the ditch. It permits the water to flow into a protected channel andthus protects the side walls of the ditch. It prevents washing of the'side wall of the ditch away around the ends of the ballle wall.

It follows that my baffle walls do not have to be re-placed frequentlyas is thecase of straight walls and the cost of the repair and upkeep ofthe ditch is thus substantially reduced. v

It will be noted that with the curved member 10 the water flows over awall four feet in length and the capacity of the ditch is thussubstantially increased without the widening of the ditch andlengthening of the wall.

The velocity and momentum is thus reduced as compared with the use ofthe straight wall without increasing the width of the ditch. I

This increase of capacity is very important resultant from the use of mywall, since it makes it possible for the ditch to take care of a greatervolume of water with a minimum of wash.

Another feature of my structure, which contributes to the permanence ofthe structure and helps to prevent washing out around the structure andthus reduces the cost of upkeep of the ditch is-found in thecorrugations or their equivalents.

It is obvious that if the dirt on the downside of the baflle'wall shouldwash out part way down the wall from the top to the bottom, so as tosubject the wall to the pressure of the water, and more important thepressure of the dirt on the up-side of the wall, so that there might bea tendency on the part of the bafile wall to tilt forwardly anddownwardly, the corrugations form anchors in the dirt in which they areembedded to prevent this tilting. This anchoring bers 11 of the wall,which thus gerve as anchors.

It will, also, be noted that the curved form of the wall tends to resistany pressure which would be likely to tilt the wall downstream.

It will be obvious that the distance from a transverse line extendingthrough the centers of the members 11 to a transverse line across theditch tothe centers of the members 11' is substantially two feet andthere is thus provided a two foot base for the baffie, instead of forexample a two inch base of a straight plank wall.

Another advantage arising from the corrugations will now be referred to.

After there has been a. considerable flow of water following a rain orin the wet season, and the ditch dries out, it is well-known that thesurface of the earth shrinks.

In Figure 5, I have illustrated by the dotted lines 19 the position ofthe soil on the up-stream side of the central member 10 when the groundis wet. In full lines at 20, there is shown the position of the soil orearth after the drying out and shrinkages has occurred.

It willbe noted that the earth close to the members 10 and 11 shrinksaway from the force Where my wall is employed it extends downwardly onlyto the first corrugation or rib on the up-stream'side of the'wall.

Thus where a straight wall is employed, this opening indicated by thenumeral 21-will lill up with dirt and 'leavesblowing in by the wind,andwhen another flow of water occurs, the water will carry fine dirt,pebbles and so forth into this opening 21 before the dirt swells again,so that when the earth on the up-stream side of the wall becomessaturated with water, thereis more dirt on the up-stream side-of-thewall than was there when the drying up process began and the swell andexpanding of the dirt on the up-stream side when the dirt becomes thusagain saturated, exercises a tremendous tending to tilt the upper partof the wall down-stream. .This is one of the factors that contributes tothe tilting of the straight wall and its ultimate washing out.

I have observed in numerous instances in the case of the use of straightwalls that this opening formed on the up-stream side of the wall by thedrying out ofithe soil extends downwardlyso far that when another rainoccurs and water flowing in the ditch travels downwardly into thisopening so far that it finds a way out around the end of the wall,thuscontributing to the washing out of the dirt at the end of the wall.The objection just mentioned is very apparent when there is a light rainaftera period of drought because the light rain does not carry much soilwith it and there is no tendency to fill up the openingas would be thecase with a real heavy rain.

Where my structure with the corruga tions and ribs is employed, it willbe obvious that the opening 21 extends downwardly fromthe surface of thebottom of the ditch.

only a very short distance and therefore only a very small amount of newdirt can be blown or washed into the opening, and

hence when the swell or expansion due to b subsequent saturation occurs,there is not such an exertion of the battle wall down stream andlesschance o the water working around the baffle wall.

pressure tending to tilt The use of a better material than wood 7 suchas galvanized 1ron or concrete or otherwise, which can be employed in mybafile wall,or course, increases the length of the life of the battlewall.

Where my wall is made of galvanized iron, and it is found necessary toremove the wall for any purpose, the earth can be removed around theupper part of the wall and clamps applied and the wall. pulled outsubstantially integral. This is absolutely impossible with the woodenwall that has been installed for any length of time.

It is almost impossible to remove a wooden wall that has been installedfor any substantial time without such injury'to the wall as to make ituseless for a later installation.

It will be obvious-from the foregoing that changes may be made in thedetails of the construction and arrangement of the various parts of myimproved baffle wall withforms shown in the drawings for the purpose ofperforming the desired functions. I claim as, my invention:

1. A baflie wall of the class described, comprising a. centralchannel-shaped member, and channel-shaped oppositely opening endmembers, said members having horizontal' corrugations of substantialdepth on their upstream sides.

2. A baflle wall of the class described,

comprising a central channel-shaped member, and channel shapedoppositely opening end members, said end members having .wings inclinedawaytherefrom substantially inclined parallel with the stream line ofthe ditch in which the wall is installed.

3. A baflle ,wall of the class described, comprising a centralchannel-shaped memer and oppositely opening channel-shaped end members,having their upper edges higher than the central member and inclinedupwardly and outwardly.

Des Moines, Iowa, October 20,"1923.

EMIL BERN.

